Preparation of detergents



Patented July 18, 1939 UNITED STATES.

PREPARATION OF DETERGENT! Wilfred s. Martin, Norwood, om, aslignor to The Procter &- Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Application August 13,1935,

Serial No. 35,983

12 Claims.

My invention relates to a process for improving the sudsing and detergent properties of sulfated alcohol detergenta'especiaily when used in hard water, and to the products thus prepared.

The water-soluble salts of sulfatedhigher' alcohols are well known to have good sudsing and detergent properties in most cases, but it has not previously been known that the sudsing and detergent properties of such compounds can be very materially improved by the use of a certain proportion of unsulfated higher alcohols in connection with same.

I have discovered that products of greatly improved sudsing and detergent properties showing greater economy in use are obtained when the above mentioned two classes of compounds are used together in rather definite proportionsand that to, obtain the best results the proportion of unsulfated alcohols present must be adjusted to a percentage within a certain range which is rather critical as will be more fully described hereinafter. A higher degree of whiteness is obtainable in the washing of soiled fabrics with my improved detergent than is obtainable with the commercial alkyl sulfate detergents alone.

The alkyl sulfate detergents referred to herein are those derived usually from natural fats and fatty oils by first reducing same to alcohols, then sulfating with a sulfating agent such as sulfuric acid, chlorsulfonic acid, etc., and finally neutralizing the sulfated product with a suitable base such as sodium or potassium hydroxide, ammonia, amines, organic bases, etc., to form water-soluble salts. It should be understood that the commercial grades of alkyl sulfates referred to herein,

such as are commonly used as detergents, always contain considerable quantities of sodium sulfate or other inorganic salt, resulting from the usual processes of manufacture, and therefore frequently contain only fifty per cent or less of the actual alkyl sulfate. Those which are most suitable for my use are the saturated products usually containing from about eight to about fourteen carbon atoms in th? alkyl radical, but

of course the alkyl sulfates prepared from hexadecyl and octadecyl alcohols may find use under certain conditions. The products obtained from coconut oil and similar oils are especially useful. These consist largely of the lauryl and myristyl 5 derivatives. These sulfated normal primary aliphatic alcohol detergents are hereinafter called alkyl sulfates for convenience.

The unsulfated alcohols which I may use for improving the properties of the alkyl sulfates 19 above mentioned when the addition of alcohols is necessary may be of several difierent classes, as follows:

(a) Individual saturated alcohols containing from about eight to about fourteen carbon atoms 15 in the molecule. These alcohols may be either primary .or secondary, and may be used either pure or in the slightly impure commercial form.

(1)) Mixtures of alcohols obtainable from natural fats (vegetable or animal oils or fats) and 20 waxes by reduction or other processes. Examples of suitable materials for this purpose are taliow, sperm oil, andcoconut oil, coconut oil being especially suitable. Other oils of the coconut oil type, as defined by Lewkowitsch in Chemical 25 Technology and Analyses of Oils, Fats and Waxes, sixth edition, 1922, pages 500 and 617, such as palm kernel oil for example} and other oils having a high saponiflcation number similar to that of coconut oil, may also be used in place 30 of coconut oil.

(c) Alcohols derived from oxidized petroleum which consist predominantly of secondary aliphatic alcohols containing in the range of about eight to about twenty-five carbon atoms per molecule. These alcohols, as shown by Luther et al. United States Patent 1,909,295, are saturated.

In adjusting the content of unsulfated alcohols 40 in the detergent mixture, I find that in some cases it is necessary to remove a portion of the alcohols already present when these are present in excessive amounts, and in other cases it is necessary to add unsulfated alcohols because these 5 are usually present in insuflicient amounts for the best results. The latter is the more common condition. In either case, I adjust the percentage of unsulfated alcohols so that it will liewithin the limits giving improved sudsing and detergent properties.

When the adjustment above mentioned requires a reduction in the amount of unsulfated alcohols, this may be accomplished either by extracting the excess alcohols by a suitable solvent, or in some cases by heating to a sufiiciently high temperature to remove unsulfated alcohols, as in the operation of spray drying or drum drying or similar methods of drying. For convenience such methods of drying are referred to in the claims as "drying operation and the products obtained thereby as dried products. When, on the other hand, the adjustment requires an increase in the amount of unsulfated alcohols, these may be added to the alkyl sulfate by any suitable mixing method either in the substantially dry form or in a water solution of the alkyl sulfate prior to use, as preferred. The method of mixing is not a part of my invention.

The proper adjustment may also be secured by suitably regulating the sulfation so as to leave the desired percentage of unsulfated alcohols. The sulfating reaction may be controlled by the 'amount and strength of the sulfating agent and/or the time and temperature of the reaction.

When alkyl sulfates containing a small amount of unsulfated alcohols are subjected to a high temperature spray drying operation or other heating treatment, they lose, mainly by evaporation, a portion of such unsulfated alcohols, and I find that such spray dried products are inferior in sudsing and detergent properties to the same material before such spray drying. If, however, I-add to the spray dried product some of the unsulfated alcohols previously mentioned, so as *to adjust the percentage to the proper amount, I obtain a product with greatly improved sudsing and detergent properties, which may be even better than these properties in the original material before spray drying.

Before proceeding to illustrate my process by examples, it should be understood that the following conditions apply in general to common laundering operations and to the examples hereinafter given. The temperatures ofmy sudsing and washing experiments were in the neighborhood of 100 F., although at temperatures both higher and lower, such as 130 E and F., for example, my detergentlmixtures show similarly improved properties; 1 j The water used in the tests had a hardness equivalent to 21 grains of calcium and magnesium calculated as calcium. carbonate in the molar ratio 2.9 calcium to. 1.0 magnesium, which is an average ratiofor hard water throughout the United States. The sudsing and detergency tests were made bystandardized procedures known to give reliable'results, comparable to those obtained in actual practice. Uniformly soiled fabrics were used and the degree of whiteness obtained was measured by a photoelectric grading apparatus entirely independent of the human equation.

In the examples now to be described, the alkyl sulfate used was the commercial sodium salt of alkyl sulfuric acid prepared from the alcohols obtained by reduction of coconut oil, but it should be understood that similar results are obtained with other alkyl sulfate detergents commonly used. The commercial allgyl sulfate detergent used had the following approximate analysis.

The unsulfated alcohols used in these examples are shown in the table below, but it should be understood that these are merely illustrative of many other alcohols included in the classes previously mentioned, and I am not limited to the alcohols shown in these examples. Lorol is a commercially available product consisting of al.

cohols obtained by reduction of coconut oil. Stenol is a commercially available product consisting essentially of saturated aliphatic alcohols containing sixteen and eighteen carbon atoms per-molecule. These various alcohols used in the experiments had the following analyses.

I d' s H d 1 i il 0 me apou y roxy ica y- Mcohol value value value droxyl value n-Octyl (ll-C5)-.. .3 1.2 426 431 n-Decyl (n-C1o) 4 l. 2 349 355 n-Dodecyl (ll- 12) 6 2. 3 296 302 n-Tetradecyl (n-C14) 2. 5 1.1 242 262 Lorol" 1.4 l. l 272 Sten0l" 214 Mixed alcohols from zed petroleum 8. 9 8. 0 209 erty, to determine the concentration required to give a definite amount of suds in water of stan'cl- I ard 21 grains hardness at F.; .secondly, to determine the concentration of the mixture required to washequally soiled fabrics to a standardsame degree. of whiteness.

Many tests were made with difierent amounts of each mixture to determine the amount required for equal results, and the results of these,

tests are shown below, wherein'Table 1 shows the effect on sudsing, and Table 2 shows the effect on detergency. The figures in the first two columns show the percentages of unsulfated alcohol and commercial alkyl sulfate .respectivelyin each mixture; the third and fourth columns show the amount of unsulfated alcohol per 100 parts actual (not commercial) alkyl sulfate in -each mixture, the amount of unsulfatedalcohol contained in the original commercial alkyl sulfate being included. In the columns under the names of the respective alcohols, wherein-n-Cs represents noctyl alcohol, n-Cm represents n-decyl alcohol, etc., the figures indicate in each case the concentration of the detergent mixture (commercial alkyl sulfate plus added unsulfated alcohol) required to give equivalent results.

Sadsing CONCENTRATION or MIXTURE IN SOLUTION RE UIRED 'ro GIVE THE snlE QUANTITY or suns (GBAMB PER. 100 o. 0.)

Ratio Percent 1 com. M11100 .110 11-0. 11-0,. 11-0,, new "Intel" "Stem!" 100 0 100 .000 .000v .000 .000 .000 .000 .010 a 01 100. .010 .002 .000 .000 .o1a .000 .000 0 04 11 100 .000 .000 .000 .010 .000 .012 .000 0 01 24 100 .004 .002 .000 .000 .002' .010 .000 12 sa :2 100- .010 .000 .012 .100 .010 .000 .010 10 e4 44 100 .050 .014 .101 1:10 .000 .100 20 s0 01 100 .040 2.1 10 100 .00

* 'IAsts 2 Detergency CONCENTRATION or MIXTURE IN SOLUTION REQEIRED TO GIVE THE ems DEGREE or WHITENESS (oBAMs P R 100 o. c.

Ratio 11001101- Percent 25? com. Mined Ale. am n-C n-Cw n-Cn m0 "Loml" "Stenci" 3m pets.

Referring now to Table 1 showing results on sudsing, it will be noted that mixtures with various percentages up to 25 per cent alcohol and 75 per cent commercial allavl sulfate were used, and that inmost cases a smaller amount of the mixture sufllced to give the standard sudsing result than when 100 per cent commercial alkyl sulfate alone was used. It is also noted, however, that in general the alcohols with higher molecular weight when used in the higher percentages become less eflicient, and may even be detrimental, but nevertheless in all cases an improvementresults when a suitable proportion of unsulfated alcohol is used with the alkyl sulfate. For example,

all the mixtures containing n-octyl' alcohol showed improved results in that a smaller amount of each of these mixtures sufliced to give the standard sudsing result than with the commercial alkyl sulfate alone. In the case of the n-tetradecyl alcohol (fourteen carbon atoms), it is seen that equal or improved results are obtained as the percentage is increased up to about 9 per cent alcohol in the mixture, but beyond this point more of the mixture was required than of the commercial alkvl sulfate alone. efficiency of the various unsulfated alcohols varies, but in all cases improved sudsing results are obtainable by adjusting the percentage within the proper range for each alcohol.

It is convenient also to express the percentage in terms of the ratio of unsulfated alcohol to the actual alkyl sulfate present as shown in the third column of the tables. As previously stated,'these figures include the three parts of unsulfated alcohol per 100 parts actual alkyl sulfate contained in the originalcommercial alkyl sulfate detergent. This indicates, for example, that in the case It is obvious that the Includes unsullated alcohol in original commercial alkyl sulfate detergent.

maximum total amount of unsulfated alcoholwhich can be used with beneficial sudsing results will apparently be somewhat below 24 parts of alcohol per 100 parts of actual alkyl sulfate. In view of variations in unsulfated alcohol content of different forms of commercial alLvl sulfate detergents covered herein,.-the amount of alcohol which can be added will depend not only on the kind of alcohol used, but also on the unsulfated alcohol content of the commercial alkyl sulfate.

Referring now to Table 2 showing results of testson detergency, results are to be interpreted in a similar way as explained in the discussion of Table 1 above. It is clear from the comparison of the two tables that a certain alcohol may be more beneficial in creating suds than in actual detergency, but in all cases a distinct improvement in detergency, as well as in sudsing, results when any of the alcohols mentioned is used in a suitable proportion. It is again apparent that the higher molecular alcohols are, in general, less efficient in detergency in the larger percentages and may then even be harmful. N-octyl alcohol (having the lowest molecular weight of the alcohols mentioned) gives outstanding results in both sudsingand detergency in all percentages tried, and can be used in this instance without harmful effect in proportions at least as high as 72 (75 minus 3) parts alcohol per 100 parts actual alkyl sulfate.

It will assist in making clear the beneficial results obtained if certain of the data shown in Tables 1 and 2 are recalculated to show the amount of commercial alkyl sulfate replaced bythe alcohol, and thus obtain a figure showing the relative efficiency of each alcohol when used in I various percentages. These data are therefore shown in the following Tables 3 and 4 calculated as follows.- Taking an example from Table 2 under n-decyl alcohol, using 6 per cent of the alco- 1101 with 94 per cent commercial alkyl sulfate detergent, we find-that .060 gram of this mixture in 100 0.0. of water was needed to wash the soiled fabric to the same whiteness as .080 gram of commercial alkyl sulfate detergent alone. Then the effllciency of this particular mixture as compared to the commercial alkyl sulfate detergent alone is expressed by the fraction in solving for X, the efiiciency of the unsulfated alcohol itself.

(.94 X 1.0) (.OSXX) =1.33

It is evident from this, therefore, that in this mixture the alcohol performs the work in detergency of 6.5 times its weight of commercial alkyl sulfate detergent.

accordance with this procedure, Tables 3 and 4 have been prepared, relating respectively to sudsing property and to detergent property, which show .the efiiciencies of the various unsulfated alcohols in these mixtures as compared to the commercial alkyl sulfate detergent present.

TABLE 3 Sudsing EFFICIENCY or ALCOHOLS Mixtures tested Percent commercial alkyl sulfate detergent.. 97 91 88 Percent unsulfated alcohol 3 9 12 Pts. actual alkyl sulfate 100 100 Pts.-unsulfated alcohol" 17 24 32 3. 5 4 4, l0. 5 7 4 8 6 2 7 1 0 1" 2 4 1 "StenoY 1 1. 5 1 Mixed'alcohols from oxidized petroleum. 3 4 1 TABLE 4 Detergencu EFFICIENCY OF ALCOHOLS Mixtures tested I l Percent commercial alkyl sulfate detergent 97 94. 91' Percent unsulfated alcohol 3 6 9 Pts. actual alkyl sulfate 100 100 100 Pts. unsulfated alcohol 10 17 24 5. 5 3. 5 -l. 5 4.5 1 0 "Stenol" 2 3. 5 1 Mixed alcohols from oxidized petroleum 8 4. 5' 6 Includes 3 parts alcohol contained in the original commercial alkyl sulfate detergent. v

' In the above Tables 3 and 4, the efficiency of each alcohol in improving the sudsing and detergency, respectively, is. shown invarious mixtures, as compared to the commercial alkyl sulfate present. It will'be noted of n-octyl alcohol, as compared with the other alcohols, that considerably greater proportions are usable without harmful efiect on the detergent property of the commercial alkyl sulfate detergent. It should be borne in mind that experimental work of this type involves unavoidably a, small experimental error which may be the explanation for any apparent inconsistencies in the data given.

In the following Table 5, the figures show the approximate maximum and the optimum amounts of unsulfated alcohol per 100 parts actual alkyl sulfate which have been found useful in. improving sudsing property. These figures were obtained from the smooth curves drawn through plotted efliciency data calculated from Tables 1 and 2 and have been corrected for the unsulfated alcohol contained in the original commercial alkyl sulfate detergent.

TABLE 5 Sudsing Pts. alcohol per 100 1133. actual alky sulfate Alcohol Mex. hts. alcohol petgmissiible ggg Wl ou ser ous harm ful effect a who] Greater than 75 63 47 22 38 22 24 12 35 22 32 17 Mixed alcohols from oxidized petroleum 32 22 Includes 3 parts alcohol contained in the original commercial alkyl sulfate detergent.

Table 6, following, likewise shows the approxi mate maximum and optimum amounts of alcohol per 100 parts actual alkyl sulfate for improving detergency.

TABLE 6 Detergency Pts. alcohol per 100 pts.

actual alkyl sulfate Alcohols.

Max. pts. al'olohol7 usable gggg w: on serious harmful effect 8109110] Greater than 75 22 "Includes 3 parts alcohol contained in the original alkyl sulfate detergent is improved when the con tent of unsulfated alcohol of any of the classes mentioned is adjusted to a suitable amount.

(2) The detergent proved as in (l). v

(3) There is in most cases an optimum figure for the use of each alcohol.

property is likewise imfor each alcohol beyond which improved results (4) There is inmost a maximum amount in either sudsing or detergency are not obtained.-

(5) The C10 and C12 alcohols are the'mosteillcient but the Cl; alcohol can be ,used in the highest percentages without harmful eifect.

(6) From-a practical standpoint, the eilect of diluent as regards sudsing property, but has some beneficial action on detergency.

In order. to secure the best results, one should I consider the purpose for which the resulting mixture is to be used, and also the kinds of alcohols available. In common laundering operations, for example, the sudsing property and the detergentproperty are of primary importance. It is possible from the data shown herein to select a suitable alcohol and to determine a suitable percentage in which markedly superior results will be obtained when this alcohol is used with a commercial alkyl sulfate detergent'deficient in alcohol content. I

Commercial alkyl sulfate detergents, such as those mentioned herein, commonly contain considerable percentages of. inorganic salts, mainly sodium sulfate, due to the process ofmanufacclaim and desireto secure by Letters Patent is:

1. The process of improving the sudsing and detergent properties of a water-soluble salt of an alkyl sulfuric acid containing eight to eighteen carbon atoms in the alkyl radical which comprises adjusting the unsulfated aliphatic alcohol content of same to an amount sufllcient to improve said properties but not below about 3 parts or in excess of '75 parts unsulfated aliphatic alcohol to 100 parts water-soluble salt, said unsulfated aliphatic alcohol being saturated and being taken from the group consisting of primary saturated aliphatic alcohols containing eight to fourteen carbon atoms in the molecule and secondary aliphatic saturated alcohols containing eight to twenty-five carbon atoms in the molecule.

2. The process of improving the sudsing and detergent properties of a water-soluble salt of a higher alkyl sulfuric acid prepared from an oil of the coconut oil type which comprises adjusting the unsulfate'd higher aliphatic alcohol content of same to an amount sumcient to improve said properties but not below about 3 parts or in excess of parts unsulfated higher aliphatic alcohol to parts water-soluble salt, said un- 'sulfated higheraliphaflc amend being sanirated' andcontainin'geighttofourteencarbonatoms inthe moleculeandbelng obtainedfromanoil of the coconut oil type. a

3. The process of improving the sudsing ahd. detergent properties of a water-soluble salt of a primary alkyl sulfuric acid containing eight to eighteen carbon atoms in the alkyl radical and containing substantially less than 12 parts unsulfated higher alcohol to 100 parts of said saltwhich comprises adding to said salt and incorporating therewith an unsulfated saturated aliphatic alcohol having eight to fourteen carbon atoms in the molecule in amount suflicient to improve said sudsing and detergent properties, said amount being such that the final product does not contain below about 3 parts of or in excess of about 12 parts of said unsulfated saturated aliphatic alcohol .to 100 parts of said salt.

4. The process of improving the sudsing. and detergent properties of a water-soluble salt of a mixture of higher alkyl sulfuric acids derived from an oil of the coconut oil type and containing substantially less than 12 parts unsulfated higher mixture of'unsulfated higher alcohols, consisting predominantly of saturated alcohols having 8 to 14 carbon atoms in themolecule and derived from an oil of the coconut oil type,iin amount sufiicient to improve said sudsing and detergent propproduct does not contain below about 3 parts of or in excess of about 12 parts of said unsulfated higher alcohol to 100 parts of said salt.

5. The process of improving the sudsing and detergent properties of a water-soluble salt of higher primary alkyl sulfuric acids derived froma mixture of higher alcohols consisting predominantly of normal dodecyl and normal tetradecyl alcohols, said salt containing substantially less than 12 parts unsulfated higher alcohol to 100 parts said salt which comprises adding to said salt and incorporating therewith n-decyl alcohol in amount sufficient to improve said sudsing and 5 detergent properties, said amount being such that the final product does not contain below about 3 parts of or in excess of about 12 parts. of said un'sulfatecl higher alcohol to 100 parts of said salt.

6. The process of improving the sudsing and detergent properties of awater-soluble salt of higher primary alkyl sulfuric acids derived from a mixture of higher alcohols consisting predominantly of normal dodecyl and normal tetradecyl alcohols, said'salt containing substantially less than 12 parts unsulfated higher alcohol to 100 parts of said salt which comprises adding to said salt and incorporating therewith n-dodecyl alcohol in amount suillcient to improvesaid sudsing and detergent properties, said amountbeing such that the final product does not contain below about 3 parts of or in excess of about l2,parts of said unsulfated higher alcohol-to 100 parts of said salt. 1

7. The process of improving the sudsing and detergent properties of a water-soluble salt of a mixture of higher alkyl sulfuric acids derived from a mixture of higher alcohols consisting predominantly of normal dodecyl and normal tetradecyl alcohols, said salt containing substantially less than 12 parts unsulfated higher alcohol to 100 parts said salt, which comprises adding to said salt and incorporating therewith n-tetradecyl alcohol in amount sufficient to improve said sudsing and detergent properties, said amount being such that the final product does not contain less than about 3 parts of or in excess of about 12 parts of said unsulfated higher alcohols to 100 parts of said salt.

8. That method of adjusting the sudsing-properties of a water-soluble salt of an alkyl sulfuric acid having eight to eighteen carbon atoms in the alkyl radical which consists in adjusting the unsulfated higher fatty alcohol contentv thereof to maximum development of said properties, the said fatty alcohol being saturated and containing 8 to 14 carbon atoms in the molecule and the content of said unsulfated fatty alcohol in said salt at said maximum development being in the range of about 12 to about 63 parts unsulfated higher fatty alcohols to 100 parts water-soluble salt.

properties of a water-soluble salt of an alkyl sulfuric acid having eight to eighteen carbon atoms in the alkyl radical which consists in adjusting the unsulfated higher fatty alcohol content thereof to maximum development of said properties,

the said fatty alcohol being saturated and containing 8 to 14 carbon atoms in the molecule and the content of said unsulfated fatty alcohol in said salt at said maximum development being in the range of about 12 to parts unsulfated higher fatty alcohol to parts water-soluble salt.

10. In the process of preparing a detergent of the alkyl sulfate type from higher alcohols ob tained from an oil of the coconut oil typeand 9. That method of adjusting the detergent consisting predominantly of saturated alcohols having 8 to 14 carbon atoms per molecule, the

step which comprises regulating the proportionv of suli'ating agent in the sulfation operation so as to obtain a final product containg from about 10 to about 22 parts higher unsulfated alcohol to 100 parts actual alkyl sulfate whereby a detergent of improved sudsing power is obtained.

11. In the process of preparing a detergent of the alkyl sulfate type from higher alcohols obtained from an oil of the coconut oil type and consisting predominantly of saturated alcohols having 8 to 14 carbon atoms per molecule, the step which comprises regulating the proportion of sulfating agent in the sulfation operation so as to obtain a final product containing from about 10 to about 17 parts higher unsulfated alcohol to said waterrsolublesalt in admixture therewith.

wm'ann s. MARTIN.

[100 parts actual alkylsuifatewhereby a detergent of improved detergent power is obtained. 

